Vibrator



H. PRELL. VIBRATOR.

APPLICATION FILED AUG. 13, 1920.

Patented Nov. 23, 1922 I/0 all:

Jim? 2271-! Z2 I E 4 5 Patented Nov. 28, 1922.

UNITED STATES 1,437,014 PATENT OFFICE.

HENRY PRELL, OF CHICAGO, ILLINOIS.

VIBRATOR.

Application filed August 13, 1920. Serial No. 403,384.

To all whom it may concern Be it known that I, HENRY PRELL, a citizen ofthe United States, residing at Chicago, in the county of Cook and Stateof Illinois, have invented certain new and useful Improvements inVibrators, of whicn the following is a specification.

This invention relates to vibrators for foundry use and is animprovement upon the vibrator shown, described and claimed in my priorapplication Ser. No. 235468 filed May 20, 1918.

The object of the present invention is to generally simplify and improvethe construction, reduce the number of parts and secure increasedetficiency and better results at lower cost.

Further objects of the invention are in part obvious and in part willappear more in detail hereinafter.

The invention comprises the construction and arrangement of partshereinafter de scribed and claimed.

In the drawings, which represent one suitable embodiment of theinvention, Fig. 1 is a sectional elevation on the line 1-1, F i 3; Fig.2 is a side view from the left, Fig. 1.

a sleeve being omitted; Fig. 3 is a plan view;

Fig. 4 is a front elevation; Fig. 5 is an end view of the hammer ofvibrating member; Figs. 6 and 7 are plan views of certain washers; andFigs. 8 and 9 are end and side views of an insulating terminal block.

The vibrator shown in the drawings comprises a hollow casing or body ofsuitable form, shown as formed of two members 1, 2 connected by capscrews 3 threaded through openings in member 2 into threaded holes inbosses 1 on member 1. Said two members are faced off smooth at 5 so asto fit closely and exclude dirt, moisture and foreign matter to thechamber 6 between the members. Both members are preferably slottedradially, such as by a narrow saw cut, as illustrated at 7, to cut theinduced current. The bosses i are also built up fairly high and theiredges 8 extend in wardly appreciably to interrupt the rcgula surface ofcontour and assist in cutting in duced current, as well as for thepurpose of increasing the exposed heat radiating surface. Member 1 isalso provided with a perforated lug or ear 9 for attaching the device tothe flask, mold or other foundry device or apparatus to which vibrationsare to be communicated.

In the relatively large portion of chamber (3 which is in member 1 is aring like ma net coil 10 the wires from which are led to binding postsor screws 11 in an insulating block 12 secured to member 1 by a pin 13and enclosed within a sleeve 14 through which the conductor wires 15 arepassed. Coil 10 may be held in place in any suitable manner but usuallyis clamped firmly between the finished surface 5 of member 2 and the endwall of chamber 6 in member 1 as shown in Fig. 1. Said coil surrounds avibrating member or hammer 16 which is of cylindrical form with asliding fit in the chamber portion 6 of member 2 from which it protrudesinto the space at the center oi? the coil. This cylindrical hammer has acentral through opening 17 in which is a shoulder 18. It is alsoprovided with a suitable num ber (12 being shown) of radially extendingslots 19 which. extend from the coil and nearly toward the opposite endwhere adja cent segments are connected by the bridges 20. One slot,marked 19 extends clear through from end to end to break or reduce theinduced current and avoid consequent heating.

Vithin the larger portion of the opening 17 is a compressionspring 21seated at one end on the shoulder 18 and at its opposite end surroundingthe head of a screw 22 which clamps firmly to the member 1 a washer likeabutment 23 shown in Fig. 7. This washer is slotted radially at 24 forthe same purpose as the hammer and is formed with a sligl'it dish orconcavity so that when it is bent down flat to its seat by screwing upthe screw 22, it forms a firm solid abutment or anvil to receive theblow and also locks the screw against turning. If desired a thin layer25 of nonmagnetic material. such as a layer of tracing cloth coated withshellac, may be inserted beneath the washer to insulate it from member 1so far as possible and thereby break the magnetic efier-t and avoidresidual magnetic efiect and stick ing, although this is not essentialand may be omitted.

In the bottom of the chamber 6 in member 2 is a washer or abutment shownin detail in Fig. 6. This washer is preferably made of such diameterthat it can be forced or driven solidly into place at the bottom ofchamber by heavy pressure and will become in effect an integral part ofthe cap or cover 2. If desired, the washer may be coated with shellacand a suitable number of paper or other thin shims can be inserted underthe washer to give it a solid bearing on a smooth surface and to alsoproperly locate the sliding member 16 in the chamber. At the center ofthe washer is an opening 27, preferably under cut, as at 28, to form ashoulder around which a suitable tool can be hooked to pull the washerout when necessary. it is also provided with a series of radial groovesor channels 29.

The operation is as follows: The conductor wire 15 is connected to asuitable source of alternating current, although in some instances thevibrator may be operated from a direct current source controlled by aninterrupter. l/Vith alternating current the hammer 16 reciprocateslongitudinally in chamber 6 in step with the cycles of the alternatingcurrent. Said hammer is made of the proper length so that a smallclearance of say seven hundredths (.07) of an inch is left between itsend and the washer 23. Therefore, when it moves in one direction underthe influence of the coil 10 it strikes the abutment or washer 23 andwhen it moves in the other direction responsive to the. change indirection of the current and also to the effect of spring 21 it strikesor engages the abutment or washer 26 with a blow. Dash pot effect isavoided by the central opening 17 in the hammer and the radial channels29 in washer 26 which allow free circulation of air and preventcushioning effect.

The hammer 16 and washer 23 are preferably made of cold rolled steelwhich is case hardened to give it a hard wear resisting outer surfacebut which leaves the inner por tion of the material soft, which assiststhe changes in magnetic polarity. Washer 26 may be made of fiber orother relatively soft and non magnetic material. The casing members land2 are usually of annealed soft gray iron to avoid these parts heatingthrough hysteresis, and which also insures a maximum blow.

Since the hammer is cylindrical and is guided in a center chamber, onlya single spring is necessary and there is no tendency of the hammer totilt or become askewin its chamber with consequent interference with itsproper movement.

What I claim is:

1. A vibrator for molding devices, coinprising a hollow casing having acentral cylindrical chamber, provided with large and small portions, acylindrical hammer member guided in the smaller part of said chamber,and a coil surrounding said member in the larger part of said chamber.

2. A vibrator for molding devices, comprising a hollow casing having acentral cylindrical chamber, provided with large and small portions, acylindrical hammer member guided in the smaller part of said chamber,and a coil surrounding said member in the larger part of said chamber,said casing being provided with abutments opposite the ends of saidmember.

3. A vibrator for molding devices, comprising a hollow casing having acentral cylindrical chamber, provided with large and small portions, acylindrical hammer mem ber guided in the smaller part of said chamber,and a coil surrounding said member in the larger part of said chamber,and means arranged to permit free circulation of air around said memberto avoid cushioning effect.

at. A vibrator for molding devices, com prising a hollow casing having achamber, a coil in said chamber and a reciprocating hammer memberactuated thereby, said member having a series of radially andtransversely extending slots one of which extends longitudinally fromend to end thereof.

5. A vibrator for molding devices, comprising a hollow casing having achamber, a coil in said chamber and a reciprocating hammer memberactuated thereby, said member having a central opening, and acompression spring in said opening.

6. A vibrator for molding devices, comprising a hollow casing having acentral well of uniform cross section throughout, a hammer member ofsubstantially the same cross-section as said well and guided therein,and a coil surrounding said member. I

In testimony whereof I aiiiX my signature.

HENRY PRELL.

